A plasma display device using an AC surface discharge PDP has already been put into practical use, in which all the pixels on a screen can simultaneously emit light in accordance with display data. The AC surface discharge PDP is a display device in which a large number of minute discharge spaces (discharge cells) sealed between two glass substrates are provided. Noble gas (discharge gas) filled in the discharge cells is discharged to form plasma and phosphors are excited by ultraviolet from the plasma. A display screen is formed from a visible light from each phosphor. Note that the method directly using the light emission from the plasma is also known.
FIG. 1 is an exploded perspective view showing a part of a structure of a plasma display panel (PDP). In the following description, components having the same function are denoted by the same reference symbols and repetitive description thereof will be omitted.
FIG. 1 shows a reflective PDP in which a front substrate 21 and a rear substrate 28 formed of glass substrates are bonded together and phosphor layers 32 for three primary colors such as red (R), green (G) and blue (B) are provided on the rear substrate 28.
The front substrate 21 has a pair of sustain discharge electrodes (also referred to as display electrodes) formed in parallel on a surface opposite to the rear substrate 28 with a certain distance therebetween. The pairs of sustain discharge electrodes are composed of transparent common electrodes (hereinafter, simply referred to as X electrodes) 22-1, 22-2, . . . and transparent independent electrodes (hereinafter, simply referred to as Y electrodes or scan electrodes) 23-1, 23-2, . . . .
The X electrodes 22-1, 22-2, . . . and the Y electrodes 23-1, 23-2, . . . are provided with opaque X bus electrodes 24-1, 24-2, . . . made of metal or the like for compensating the conductivity of the transparent electrodes and opaque Y bus electrodes 25-1, 25-2, . . . made of metal or the like for compensating the conductivity of the transparent electrodes, respectively, in an arrow direction D2 (row direction) in FIG. 2.
Note that the X electrodes 22-1, 22-2, . . . , the Y electrodes 23-1, 23-2, . . . , the X bus electrodes 24-1, 24-2, . . . and the Y bus electrodes 25-1, 25-2, . . . are insulated from discharge for AC drive. In other words, these electrodes are covered with a dielectric layer 26 generally made of low melting point glass (for example, lead glass: a relative dielectric constant ∈r is 12 to 14) and the dielectric layer 26 is covered with a protection film 27.
The rear substrate 28 has address electrodes (hereinafter, simply referred to as A electrodes) 29 which extend in a direction perpendicular to the X electrodes 22-1, 22-2, . . . and the Y electrodes 23-1, 23-2, . . . of the front substrate 21, on a surface opposite to the front substrate 21, and the A electrodes 29 are covered with a dielectric layer 30. The A electrodes 29 are provided so as to extend in an arrow direction D1 (column direction) of FIG. 2, and barrier ribs (ribs) 31 for separating the A electrodes 29 are provided on the dielectric layer 30 in order to prevent the expansion of the discharge (to define discharge regions). The phosphor layers 32 for emitting read, green, and blue lights are sequentially applied in a stripe shape to cover the grooves between the barrier ribs 31.
FIG. 2 is a cross-sectional view of the principal part of the plasma display panel viewed in the direction D2 in the exploded perspective view of FIG. 1, which shows one discharge cell which is the minimum unit of a pixel. In FIG. 2, a boundary between the discharge cells is a position shown by a dashed line.
In FIG. 2, a reference numeral 33 denotes a discharge space in which discharge gas for generating plasma 10 is filled. When a voltage is applied between the electrodes, the plasma 10 is generated by ionization of the discharge gas. FIG. 2 schematically shows how the plasma 10 is generated. Ultraviolet from the plasma 10 excites the phosphor 32 to emit light, and the light emission from the phosphor 32 transmits through the front substrate 21 and the light emission from the respective discharge cells form the display screen.
FIG. 3 is a plan view of the plasma display panel showing one example of an electrode shape viewed in a direction D3 in the exploded perspective view of FIG. 1. In FIG. 3, a portion surrounded by a dashed line indicates substantially one discharge cell CE.
The shape of transparent electrodes in FIG. 3 is of a so-called straight electrode. In addition, electrodes having the shape shown in FIG. 4 and FIG. 5 are also known for improving the performance of the PDP.
More specifically, as a surface discharge plasma display device capable of the display using the discharge light emission at relatively low power consumption even in a large display size, a device has been proposed, in which at least one row electrode of a pair of row electrodes has a body extending in a horizontal direction and a projection which projects from the body to the other row electrode in a vertical direction for each pixel cell and a length of the projection is 400 to 1000 μm (for example, Japanese Patent No. 3352821 (Japanese Patent Application Laid-Open Publication No. 08-022772) (Patent Document 1)).
Further, in order to manufacture a gas discharge display device having a uniform dielectric layer with a low relative dielectric constant, a device has been proposed, in which a layer which isotropically covers an underlying surface of a formed film is formed as a dielectric layer by the plasma vapor deposition, on a surface of a substrate structure after the X and Y electrodes have been disposed (for example, Japanese Patent No. 3481142 (Japanese Patent Application Laid-Open Publication No. 2000-021304) (Patent Document 2)).
Furthermore, in order to restrict the expansion of the discharge in a column direction to enhance the resolution, a device has been proposed, in which the X and Y electrodes are formed so as to have a shape composed of one band-shaped base extending throughout the full length of the screen in the row direction and a projection which projects to other adjacent row electrode from the base for each column (for example, Japanese Patent Application Laid-Open Publication No. 2000-113828 (Patent Document 3)).
In addition, in order to prevent decrease in luminance and erroneous discharge in the discharge cells to achieve the high definition, a device has also been proposed, in which the respective X and Y electrodes constituting the row electrode pair have transparent electrodes which project toward the other respective paired row electrodes from the bus electrodes extending in the row direction for each discharge cell and are opposite to each other via a predetermined discharge gap (for example, Japanese Patent No. 3334874 (Japanese Patent Application Laid-Open Publication No. 2002-163990) (Patent Document 4)).
Also, in order to manufacture a gas discharge display device having a uniform dielectric layer with a low relative dielectric constant, a device has been proposed, in which a layer which isotropically covers an underlying surface of a formed film and is made of silicon compound having a compression stress is formed as a dielectric layer by the plasma vapor deposition, on a surface of a substrate structure after the X and Y electrodes have been disposed (for example, Japanese Patent Application Laid-Open Publication No. 2004-006426 (Patent Document 5)).